What equation is used to determine a patient's Total Lung Capacity (TLC)?

Total Lung Capacity (TLC) is the total amount of air that the lungs can hold when filled to capacity. It is composed of several lung volumes, specifically the Functional Residual Capacity (FRC), which is the volume of air remaining in the lungs after normal expiration, and the Inspiratory Capacity (IC), which represents the maximum amount of air that can be inhaled after a normal expiration.

FRC is itself made up of the Expiratory Reserve Volume (ERV) and the Residual Volume (RV), while IC includes the Tidal Volume (TV) and the Inspiratory Reserve Volume (IRV). Combining FRC and IC gives the Total Lung Capacity, which outlines the relationship of these lung volumes and provides a comprehensive measure of lung capacity.

Therefore, using the equation that combines FRC and IC accurately determines Total Lung Capacity, making it the correct choice.